Naturwissenschaften (2011) 98:407–423 DOI 10.1007/s00114-011-0786-z ORIGINAL PAPER Giant rhinoceros Paraceratherium and other vertebrates from Oligocene and middle Miocene deposits of the Kağızman-Tuzluca Basin, Eastern Turkey Sevket Sen & Pierre-Olivier Antoine & Baki Varol & Turhan Ayyildiz & Koray Sözeri Received: 22 December 2010 /Revised: 17 February 2011 /Accepted: 18 February 2011 /Published online: 5 April 2011 # Springer-Verlag 2011 Abstract A recent fieldwork in the Kağızman-Tuzluca Introduction Basin in northeastern Turkey led us to the discovery of three vertebrate localities which yielded some limb bones of Eastern Turkey is an almost total Terra incognita for the giant rhino Paraceratherium, a crocodile tooth, and vertebrate paleontology, except for eight localities in the some small mammals, respectively. These discoveries Elazığ,Muş, and Pasinler basins, of which Ünay and de allowed, for the first time to date some parts of the Bruijn (1998) reported Pliocene rodent fossils, and a sedimentary units of this basin. This study also shows that locality in the Posof-Ahaltsikhe Basin at the Turkish- the dispersal area of Paraceratherium is wider than it was Georgian border yielded a rich Late Eocene/Early Oligo- known before. Eastern Turkey has several Cenozoic cene small mammalian fauna (De Bruijn et al. 2003). sedimentary basins formed during the collision of the Otherwise, the age of the Cenozoic terrestrial sedimentary Arabian and Eurasian plates. They are poorly documented deposits are given by their relative position with respect to for vertebrate paleontology. Consequently, the timing of marine deposits, few pollen data, or they are dated as tectonic activities, which led to the formation of the East “undifferentiated Neogene”. In fact, Cenozoic terrestrial Anatolian accretionary complex, is not constrained enough deposits formed in compressional intermountane or pull- with a solid chronological framework. This study provides apart basins cover about half of Eastern Turkey, the the first biostratigraphic evidences for the infill under the sedimentary infill of which is potentially suitable for control of the compressive tectonic regime, which built the preservation of vertebrate fossils (Şengöretal.1985, East Anatolian Plateau. 2008). In addition, most of these basins are in part underlain and in part filled with thick sedimentary Keywords Cricetidae . Erinaceidae . Paraceratherium . sequences spanning in age from late Cretaceous up to the Oligocene . Miocene . Turkey Pleistocene (Koçyiğit et al. 2001; Şengör et al. 2008). The age of terrestrial deposits is poorly constrained by some mollusk and pollen data (Sancay et al. 2006), and S. Sen (*) consequently the filling history of these basins and their Laboratoire de Paléontologie du Muséum, related tectonic context are often debated because of the CR2P-CNRS, 8 rue Buffon, 75005 Paris, France lack of reliable age data. A better knowledge of the e-mail: [email protected] depositional chronology of these basins will in turn contribute to the timing of related tectonic events in the P.-O. Antoine region. Institut des Sciences de l’Evolution de Montpellier, CC064, Place Eugène Bataillon, The study area is situated in NE Turkey, near the 34095 Montpellier, France Armenian border, in the intramountane, i.e. compressional : : Kağızman-Tuzluca Basin (Fig. 1), which continues into B. Varol T. Ayyildiz K. Sözeri Armenia south of Yerevan as Aras/Araxes or Hoktemberian Faculty of Engineering, Department of Geological Engineering, Ankara University, Basin, filled with lagoonal marine to continental/lacustrine Ankara, Turkey and alluvial deposits broadly dated (similar to their Turkish 408 Naturwissenschaften (2011) 98:407–423 Fig. 1 Geological map of the Kağızman-Tuzluca Basin in the region of Tuzluca, and the location of vertebrate fossil sites Naturwissenschaften (2011) 98:407–423 409 counterparts) as Early–Middle Miocene covered by much graphic and paleobiogeographic significance and input. In later alluvium of Quaternary age (Balian 1969) or as Late addition, the discovery of the giant rhino Paraceratherium Oligocene to Late Miocene by Gabrielyan (1964). Eastern in the Kağızman-Tuzluca Basin questions the environ- Turkey, also known in the geological literature as the East mental context and paleobiogeographic relations of this Anatolian High Plateau forming the northeastern part of the area during the Late Paleogene and Early Neogene times. broader Turkish-Iranian High Plateau (Şengör et al. 2008), has many Cenozoic sedimentary basins formed under diverse strain regimes, ranging from shortening to trans- Geological setting pressional and transtensional dictated by the local vagaries of the broadly north–south shortening and east–west The study area is within the Eastern Turkish High extension generated by the collision of the Arabian and Plateau lying east of the intersection point of the North Eurasian plates. Some of these basins are as large as several and East Anatolian faults at Karlıova (see Şengör et al. hundred square kilometres (e.g. Elazığ,Muş and Van Gölü 1985, 2008) where folds, thrust and strike-slip faults, and basins), whereas others, situated farther to the north, are large-scale extensional fractures related to a shortening much smaller (e.g. Tercan, Askale, Pasinler and Kağızman- regime have been developing as a result of continent– Tuzluca basins). For the Kağızman-Tuzluca Basin, Yılmaz continent collision during the Neotectonic episode (Şengör and Şener (1984, Fig. 12) and Şaroğlu and Yılmaz (1986, and Yılmaz 1981). Simultaneously with the shortening Fig. 10) published some sketch stratigraphic columns and phase, structural basins developed such as intermountane attributed a Pliocene age to the Cenozoic terrestrial and pull-apart basins. The Kağızman-Tuzluca Basin, deposits. As we will see below, the terrestrial deposits in which is interpreted as a ramp (Şengör et al. 1985)or the Kağızman-Tuzluca Basin have instead a time-range pull-apart basin (Şaroğlu and Yılmaz 1986; Varol et al. covering the Oligocene–Miocene interval, closer to the 2009), is also accompanied by intense volcanism, which dating from its easterly continuation in Armenia. started during the Late Miocene. Our mapping (Fig. 1)has In May 2010, our team aimed to establish a chrono- shown that the basin has suffered shortening and it is thus logical framework for the Cenozoic deposits outcropping in most likely to be an intermountane ramp valley (half- the Tuzluca area of the Kağızman-Tuzluca Basin. Our ramp?) basin. Its orientation is also incompatible with a search of vertebrate fossils led us to the discovery of some pull-apart origin. The sub-active Holocene volcanic cen- vertebrate remains in three formations. These fossils are ters, such as Ararat (Ağrı) Mountain, have been controlled characteristic enough to date some stratigraphic units of this by active faults within the pull-apart basin structures basin, and are also well interesting for the knowledge of (Şaroğlu and Yılmaz 1986;Yılmaz et al. 1998;Karakhanian several vertebrate groups. et al. 2002). The Kağızman-Tuzluca Basin occupies a As described below, the sedimentary units of the Tuzluca narrow area (40 km long and 10–15 km wide), which is area yielded some remains of a crocodile, an insectivore, crossed by the Aras River and continues into Armenia as two rodents and two rhinoceroses. For the last group, we the Araxes or Hoktemberian Basin (Balian 1969). It is collected four bones of a giant rhino, referable to Para- bordered by the Cretaceous ophiolitic basement rocks of the ceratherium. Paraceratherium is for Cenozoic land mam- Kağızman Complex to the south and the Late Miocene– mals what the largest dinosaurs are for the Mesozoic world. Pliocene mafic volcanic rocks of the Kars Plateau to the Indeed, Paraceratherium is recognized as being among the north and west. largest land mammals that ever lived on Earth (Fortelius Detailed mapping of the Cenozoic deposits in the and Kappelman 1993). This genus and its relatives, eastern part of this basin allowed the recognition of grouped in the indricotheriine Hyracodontidae, are well- five successive sedimentary units (Varol et al. 2009). known from the Oligocene of Asia (China, Mongolia, The Cenozoic infill starts with the marine deposits of the Kazakhstan, and Pakistan), but scarcely in western Asia and Kaan Formation (Fig. 2), which crop out in a limited area southeastern Europe (Georgia, Turkey, Bulgaria and Romania; in the southwestern margin of the basin. They mainly e.g. Antoine et al. 2008). Their dispersal history may be consist of foraminifera bearing sandy limestones, rich in correlated with the paleogeographic evolution of the nummulites, dominated by Nummulites fichteli MICHEL- Alpine-Himalayan belt, in particular in the Middle East, OTTI, 1841, indicating an Early Oligocene age, more and the environmental conditions, which prevailed during precisely the Rupelian SB 21–22 zones (Sirel, oral the Oligocene. communication). This paper aims to provide a comprehensive stratigraphy This marine unit is overlain by the Güngörmez Formation of the Kağızman-Tuzluca Basin in the Tuzluca area, and to with a local unconformity. The Güngörmez Formation shows describe the vertebrate remains collected from three strati- a complex depositional character, represented by vertical and graphic units, for their identification and their biostrati- lateral transitions of fluvial and deltaic deposits (Fig. 3a, b). 410 Naturwissenschaften (2011) 98:407–423 Fig. 2 Cenozoic stratigraphy of